What causes "${label} returned a malformed image URL" in jackwener/OpenCLI?

Inspect the raw pages API payload for the illustration to see what the url field actually contains

jackwener/OpenCLI · error · CommandExecutionError

${label} returned a malformed image URL

Error message

${label} returned a malformed image URL

What it means

This CommandExecutionError is thrown by parsePixivImageUrl in clis/pixiv/bookmark-download.js:36-41 when the image URL string from the Pixiv API cannot be parsed by the URL constructor. The value is a non-empty string but not a valid absolute URL (new URL(value) throws).

Source

Thrown at clis/pixiv/bookmark-download.js:40

  ['.gif', 'image/gif'],
  ['.webp', 'image/webp'],
]);

function requireExecute(value) {
  if (value !== true) {
    throw new ArgumentError('Refusing to write local Pixiv downloads: pass --execute');
  }
}

function parsePixivImageUrl(value, label) {
  if (typeof value !== 'string' || !value) {
    throw new CommandExecutionError(`${label} returned a missing image URL`);
  }
  let url;
  try {
    url = new URL(value);
  } catch {
    throw new CommandExecutionError(`${label} returned a malformed image URL`);
  }
  const extension = path.extname(url.pathname).toLowerCase();
  const contentType = IMAGE_CONTENT_TYPES.get(extension);
  if (url.protocol !== 'https:' || url.hostname !== 'i.pximg.net' || url.username || url.password || url.port || !contentType) {
    throw new CommandExecutionError(`${label} returned an untrusted Pixiv image URL`);
  }
  return { url: url.href, extension, contentType };
}

async function prepareIllustPlan(page, row, outputRoot) {
  const pages = await pixivFetch(page, `/ajax/illust/${row.illust_id}/pages`, {
    notFoundMsg: `Illustration not found: ${row.illust_id}`,
  });
  if (!Array.isArray(pages)) {
    throw new CommandExecutionError('Pixiv pages API returned malformed payload');
  }
  if (pages.length === 0) {
    throw new EmptyResultError('pixiv bookmark-download', `No images found for illustration ${row.illust_id}.`);

View on GitHub (pinned to 49907e53dc)

Solutions

Inspect the raw pages API payload for the illustration to see what the url field actually contains
If the value is protocol-relative or relative, normalize it against https://i.pximg.net before parsing
Re-authenticate or verify the illustration is accessible — restricted works can return placeholder values
Update the CLI to handle the new Pixiv response format if the API schema changed

Defensive patterns

Strategy: type-guard

Validate before calling

function looksLikeAbsoluteUrl(value) {
  if (typeof value !== 'string' || !value) return false;
  try { new URL(value); return true; } catch { return false; }
}
const raw = entry.urls.original || entry.urls.regular;
if (!looksLikeAbsoluteUrl(raw)) {
  console.warn('Non-absolute URL from API:', raw);
}

Type guard

function isValidUrl(value) {
  if (typeof value !== 'string' || !value) return false;
  try { new URL(value); return true; } catch { return false; }
}

Try / catch

try {
  const parsed = parsePixivImageUrl(value, label);
} catch (e) {
  if (e instanceof CommandExecutionError && e.message.includes('malformed image URL')) {
    // Normalize protocol-relative or relative paths before retrying
    const absolute = value.startsWith('//') ? 'https:' + value : new URL(value, 'https://i.pximg.net/').href;
    parsed = parsePixivImageUrl(absolute, label);
  } else {
    throw e;
  }
}

Prevention

Validate URLs from the API with new URL() before further processing
Normalize protocol-relative ('//...') or relative paths against https://i.pximg.net upstream of the parser
Log raw API payloads when a schema change is suspected
Re-authenticate when payloads look degraded or contain placeholder values

When it happens

Trigger: The urls.original or urls.regular field from the /ajax/illust/<id>/pages response is a non-URL string (e.g. a relative path, placeholder text, or HTML fragment), so new URL(value) throws at clis/pixiv/bookmark-download.js:38.

Common situations: Pixiv API returning relative or protocol-relative paths after a schema change; a proxy/mirror or cached response with corrupted fields; scraping-style integrations passing non-URL strings into the parser; localized error text landing in the url field on restricted works.

Understand the failure class

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29). Data as JSON: /api/errors/c2c254bd6946936f. Report an issue: GitHub.